1. Field of the Invention
The present invention is directed to a novel class of compounds that have utility as pesticides, particularly in the control of nematodes, insects and acarids. Thus, the present invention is particularly directed to a class of compounds which are effective as nematicides, insecticides and acaricides.
Pests, such as nematodes, insects and acarids, pose serious problems to agriculture. A wide variety of field crops are menaced by nematodes, insects and acarids. Such valuable crops as tobacco, corn, soybeans, peanuts, citrus, potato and sugar beets all require protection from the ravages of nematodes, insects, and acarids.
Of particular concern is the protection of tobacco, soybeans and peanuts. These are important commercial crops. Those skilled in the art are aware that these crops are subject to destruction from soil pests, especially the root knot nematode. Nematodes invade and cause severe damage to the roots of such plants. Protection against nematodes is particularly acute in the absence of crop rotation. Plants attacked by this nematode produce lower yields and significant crop loss may result.
Nematicidal compounds with insecticidal activity against soil larvae such as wireworms, cutworms and rootworms, against sucking pests such as aphids, and against foliar feeding beetles and mites provide more complete plant protection. It is appreciated that there are known methods for non-fumigant control of nematodes, insects and mites. However, these methods, the most common of which is the application of carbamate and organophosphorus compounds, are being eliminated because of the high levels of mammalian toxicity in several products. It is highly important to emphasize the requirement that any soil pesticide which is employed be capable of being applied in sufficiently low concentration to ensure environmental safety.
2. Description of Related Art
U.S. Pat. Nos. 4,327,090; 4,424,215; 4,568,668; 4,612,306; and 4,670,425 are directed to various classes of oximinophosphoric acid derivatives said to have application as pesticides. All of these derivatives are formed by reacting a thiono or thiol phosphoric or phosphonic acid ester or amide halide with a compound which provides the derivative portion of the oximinophosphoric acid derivative compound. These compounds include an alpha-cyano group. None of the compounds includes a tetrazolidinone ring.
U.S. Pat. No. 4,330,536 is directed to oxime phosphates which include pyridyloxy benzaldehyde groups. Moreover, a tetrazolinone ring is not part of the oxime phosphate structure.
U.S. Pat. No. 4,339,444 is directed to oxime phosphate compounds said to have insecticidal, miticidal and nematicidal activity. The compounds have an alpha-alkoxy substituent. The inclusion of this substituent in an oxime phosphate compound is distinguished from an oxime phosphate compound which includes a tetrazolidinone ring.
U.S. Pat. No. 4,535,077 is directed to O-ethyl S,S-dialkyl phosphorodithioates said to be effective against soil borne insects and nematodes. Those compounds are completely structurally removed from an oxime phosphate compound.
U.S. Pat. No. 4,618,365 is directed to a substituted tetrazolinone said to be useful as a preemergence and postemergence herbicide. Those compounds, however, are remote from oxime phosphate compounds, and do not include phosphorus atoms.
U.S. Pat. No. 4,839,439 is directed to a class of phosphorus substituted tetrazolinone compounds said to be useful in pesticidal compositions.
The above remarks establish the need in the art for a new class of compounds, useful as a pesticide, especially against soil insects, nematodes and acarids that can control these harmful pests over long periods of time, albeit at very low concentrations.